Total hip arthroplasty is a common arthroplasty surgery, only second to the knee arthroplasty
Unlike in the knee, a dreaded complication not only for the patient, but also the surgeon is dislocation of the replaced hip
Surgeons shy away from the posterior approach to the hip (which is an otherwise an excellent technique), for this single reason
In posterior approach to the hip, gluteus medius and minimus are not disturbed, the short external rotators are respected and sutured back
The remaining structure, a surgeon has to address to reduce dislocation is the capsule
It is now proven that the capsulotomy and closure is better than capsulectomy ( which used to be the norm) in in total hip replacements
Different techniques of capsulotomy and closure has been described, namely Longitudinal, T capsulotomy, Z capsulotomy, longitudinal with two anterior incisions one superior and another inferior
We describe a new technique of capsulotomy of the hip, named Lambda capsulotomy
see illustration 1
This involves making a longitudinal capsulotomy, along the long axis of the neck of femur
then antero superior limb of capsulotomy, parallel to the superior fibres of Ischio femoral ligament is made
This leaves three capsular flaps, namely long posterior flap, antero superior flap and antero inferior flap
The anatomical basis of the capsulotomy and repair is by respecting the ischiofemoral ligament and more importantly the zona orbicularis
The capsule of the hip joint is not cylindrical, but larger diameter at the head level and narrower at the neck level
see illustration 2
The ischiofemoral ligament has longitudinal fibres running obliquely from the ischial part of the acetabulum superiorly to the femoral neck inferiorly
Zona orbicularis is a capsular condensation of circular fibres running around the narrowest part of the femoral neck forming a natural noose. Illustration 3
The lambda capsulotomy allows repair of the ischiofemoral ligament and more importantly restores the natural noose around the femoral neck, namely the zona orbicularis
Illustrations
1. The Lambda cut
A long longitudinal cut along the long axis of the neck
A smaller antero superior cut running from this longitudinal cut following the natural curvature of the acetabulum
2. The circumference of the capsule at the level of femoral head is more than the circumference of the capsule at the level of the neck
3. Zona orbicularis
4. the lambda capsulotomy
